Key Features and Architecture of PHP 7 and PHP 8

PHP 8 Features : JIT compiler that builds on OpCache, match expression for value mapping, union types for multiple type declarations, static return type, WeakMap allowing objects as keys, various class changes such as variadic parameter inheritance, late static binding, new and instanceof with arbitrary expressions, stringable interface, and abstract private trait methods.

PHP 7 New Features (vs. PHP 5) : scalar type declarations, return type declarations, null‑coalescing operator (??), enhanced use statements for importing classes/functions/constants, anonymous classes via new class , roughly double performance, and native 64‑bit support.

Why PHP 7 Is Faster Than PHP 5 : reduced variable storage size, improved array/hash layout for better cache locality, and optimized function call mechanisms.

PHP 7 Execution Process : lexical analysis (tokenization), syntax analysis producing an AST, compilation of the AST into opcodes, and virtual‑machine interpretation of those opcodes.

Web‑Mode PHP Lifecycle (SAPI) : module initialization (MINIT), request initialization, script execution (compiling to opcodes and running), request shutdown (output flushing and cleanup), and module shutdown (resource release).

PHP 7 Architecture : Zend Engine (lexical/syntax analysis, AST, opcodes, variable and memory management), PHP layer (SAPI binding, safe‑mode/open‑basedir checks, I/O functions), SAPI implementations (CLI, FPM, etc.), and extensions built on the Zend Engine API.

Data Implementation : PHP’s underlying data structures are hash tables.

Garbage Collection : PHP uses reference‑counting GC; each object holds a refcount that increments on new references and decrements when references are removed, freeing memory when the count reaches zero.

PHP‑FPM Architecture and Optimization : master‑worker model where workers handle requests and the master manages processes; optimization can involve tuning the minimum and maximum number of worker processes to match concurrency demands.